package/xterm: bump version to 401
See the Changes here:
https://invisible-island.net/xterm/xterm.log.html
COPYING was changed, the year was bumped and some extra
license information was removed.
Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>